US2920379A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making perpendicular magnetic recording head
Assignee: International Business Machines Corp
•
Filing: 1956-11-06
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Granted: 1960-01-12
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Expires: 1976-11-06
Abstract
No abstract record available.
Inventors
- 👤 Jacob J Hagopian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 21:45
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/17; G11B5/10; G11B5/11; G11B5/1278; G11B5/187; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/4906; Y10T29/49066
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
DE617796C
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US2089287A
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US2205669A
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US2523515A
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US2560926A
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US2754569A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-01-11 | 1963-07-13 | 1964-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-01-11 | 1967-07-13 | 1968-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-01-11 | 1971-07-13 | 1972-01-12 | $7700.00 | Window Closed / Lapsed |